On Wed, Dec 01, 2010 at 11:16:47AM -0800, Mike Ryan wrote:
> [one more minor change which is needed on older kernels]
>
> Add an option to specify the host IP to send multicast packets from when
> using a multicast socket for networking. The option takes an IP address
> and sets the IP_MULTICAST_IF socket option, which causes the packets to
> use that IP's interface as an egress.
>
> This is useful if the host machine has several interfaces with several
> virtual networks across disparate interfaces.
>
> Signed-off-by: Mike Ryan <miker...@isi.edu>
Applied. I tweaked style in one place ({} in if)
and the commit message a bit.
> ---
> net.c | 4 ++++
> net/socket.c | 51 ++++++++++++++++++++++++++++++++++++++-------------
> qemu-options.hx | 11 +++++++++--
> 3 files changed, 51 insertions(+), 15 deletions(-)
>
> diff --git a/net.c b/net.c
> index c5e6063..9ba5be2 100644
> --- a/net.c
> +++ b/net.c
> @@ -1050,6 +1050,10 @@ static const struct {
> .name = "mcast",
> .type = QEMU_OPT_STRING,
> .help = "UDP multicast address and port number",
> + }, {
> + .name = "localaddr",
> + .type = QEMU_OPT_STRING,
> + .help = "source address for multicast packets",
> },
> { /* end of list */ }
> },
> diff --git a/net/socket.c b/net/socket.c
> index 1c4e153..df777ff 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -149,7 +149,7 @@ static void net_socket_send_dgram(void *opaque)
> qemu_send_packet(&s->nc, s->buf, size);
> }
>
> -static int net_socket_mcast_create(struct sockaddr_in *mcastaddr)
> +static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct
> in_addr *localaddr)
> {
> struct ip_mreq imr;
> int fd;
> @@ -183,7 +183,10 @@ static int net_socket_mcast_create(struct sockaddr_in
> *mcastaddr)
>
> /* Add host to multicast group */
> imr.imr_multiaddr = mcastaddr->sin_addr;
> - imr.imr_interface.s_addr = htonl(INADDR_ANY);
> + if (localaddr != NULL)
> + imr.imr_interface = *localaddr;
> + else
> + imr.imr_interface.s_addr = htonl(INADDR_ANY);
>
> ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
> (const char *)&imr, sizeof(struct ip_mreq));
> @@ -201,6 +204,15 @@ static int net_socket_mcast_create(struct sockaddr_in
> *mcastaddr)
> goto fail;
> }
>
> + /* If a bind address is given, only send packets from that address */
> + if (localaddr != NULL) {
> + ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, localaddr,
> sizeof(*localaddr));
> + if (ret < 0) {
> + perror("setsockopt(IP_MULTICAST_IF)");
> + goto fail;
> + }
> + }
> +
> socket_set_nonblock(fd);
> return fd;
> fail:
> @@ -248,7 +260,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState
> *vlan,
> return NULL;
> }
> /* clone dgram socket */
> - newfd = net_socket_mcast_create(&saddr);
> + newfd = net_socket_mcast_create(&saddr, NULL);
> if (newfd < 0) {
> /* error already reported by net_socket_mcast_create() */
> close(fd);
> @@ -468,17 +480,26 @@ static int net_socket_connect_init(VLANState *vlan,
> static int net_socket_mcast_init(VLANState *vlan,
> const char *model,
> const char *name,
> - const char *host_str)
> + const char *host_str,
> + const char *localaddr_str)
> {
> NetSocketState *s;
> int fd;
> struct sockaddr_in saddr;
> + struct in_addr localaddr, *param_localaddr;
>
> if (parse_host_port(&saddr, host_str) < 0)
> return -1;
>
> + if (localaddr_str != NULL) {
> + if (inet_aton(localaddr_str, &localaddr) == 0)
> + return -1;
> + param_localaddr = &localaddr;
> + } else {
> + param_localaddr = NULL;
> + }
>
> - fd = net_socket_mcast_create(&saddr);
> + fd = net_socket_mcast_create(&saddr, param_localaddr);
> if (fd < 0)
> return -1;
>
> @@ -505,8 +526,9 @@ int net_init_socket(QemuOpts *opts,
>
> if (qemu_opt_get(opts, "listen") ||
> qemu_opt_get(opts, "connect") ||
> - qemu_opt_get(opts, "mcast")) {
> - error_report("listen=, connect= and mcast= is invalid with fd=");
> + qemu_opt_get(opts, "mcast") ||
> + qemu_opt_get(opts, "localaddr")) {
> + error_report("listen=, connect=, mcast= and localaddr= is
> invalid with fd=\n");
> return -1;
> }
>
> @@ -524,8 +546,9 @@ int net_init_socket(QemuOpts *opts,
>
> if (qemu_opt_get(opts, "fd") ||
> qemu_opt_get(opts, "connect") ||
> - qemu_opt_get(opts, "mcast")) {
> - error_report("fd=, connect= and mcast= is invalid with listen=");
> + qemu_opt_get(opts, "mcast") ||
> + qemu_opt_get(opts, "localaddr")) {
> + error_report("fd=, connect=, mcast= and localaddr= is invalid
> with listen=\n");
> return -1;
> }
>
> @@ -539,8 +562,9 @@ int net_init_socket(QemuOpts *opts,
>
> if (qemu_opt_get(opts, "fd") ||
> qemu_opt_get(opts, "listen") ||
> - qemu_opt_get(opts, "mcast")) {
> - error_report("fd=, listen= and mcast= is invalid with connect=");
> + qemu_opt_get(opts, "mcast") ||
> + qemu_opt_get(opts, "localaddr")) {
> + error_report("fd=, listen=, mcast= and localaddr= is invalid
> with connect=\n");
> return -1;
> }
>
> @@ -550,7 +574,7 @@ int net_init_socket(QemuOpts *opts,
> return -1;
> }
> } else if (qemu_opt_get(opts, "mcast")) {
> - const char *mcast;
> + const char *mcast, *localaddr;
>
> if (qemu_opt_get(opts, "fd") ||
> qemu_opt_get(opts, "connect") ||
> @@ -560,8 +584,9 @@ int net_init_socket(QemuOpts *opts,
> }
>
> mcast = qemu_opt_get(opts, "mcast");
> + localaddr = qemu_opt_get(opts, "localaddr");
>
> - if (net_socket_mcast_init(vlan, "socket", name, mcast) == -1) {
> + if (net_socket_mcast_init(vlan, "socket", name, mcast, localaddr) ==
> -1) {
> return -1;
> }
> } else {
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 4d99a58..accd16a 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1061,8 +1061,9 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
> #endif
> "-net
> socket[,vlan=n][,name=str][,fd=h][,listen=[host]:port][,connect=host:port]\n"
> " connect the vlan 'n' to another VLAN using a socket
> connection\n"
> - "-net socket[,vlan=n][,name=str][,fd=h][,mcast=maddr:port]\n"
> + "-net
> socket[,vlan=n][,name=str][,fd=h][,mcast=maddr:port[,localaddr=addr]]\n"
> " connect the vlan 'n' to multicast maddr and port\n"
> + " use 'localaddr=addr' to specify the host address to
> send packets from\n"
> #ifdef CONFIG_VDE
> "-net
> vde[,vlan=n][,name=str][,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
> " connect the vlan 'n' to port 'n' of a vde switch
> running\n"
> @@ -1256,7 +1257,7 @@ qemu linux.img -net nic,macaddr=52:54:00:12:34:57 \
> -net socket,connect=127.0.0.1:1234
> @end example
>
> -...@item -net socket[,vl...@var{n}][,na...@var{name}][,f...@var{h}]
> [,mca...@var{maddr}:@var{port}]
> +...@item -net
> socket[,vl...@var{n}][,na...@var{name}][,f...@var{h}][,mca...@var{maddr}:@var{port}[,localad...@var{addr}]]
>
> Create a VLAN @var{n} shared with another QEMU virtual
> machines using a UDP multicast socket, effectively making a bus for
> @@ -1296,6 +1297,12 @@ qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \
> /path/to/linux ubd0=/path/to/root_fs eth0=mcast
> @end example
>
> +Example (send packets from host's 1.2.3.4):
> +...@example
> +qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \
> + -net socket,mcast=239.192.168.1:1102,localaddr=1.2.3.4
> +...@end example
> +
> @item -net vde[,vl...@var{n}][,na...@var{name}][,so...@var{socketpath}]
> [,po...@var{n}][,gro...@var{groupname}][,mo...@var{octalmode}]
> Connect VLAN @var{n} to PORT @var{n} of a vde switch running on host and
> listening for incoming connections on @var{socketpath}. Use GROUP
> @var{groupname}
> --
> 1.7.0.4
